You just looking to have some nice stickers, or looking to actually meet FDA regulations here? If you're trying to go with FDA, you may not be able to pull it off since they have some dumb strict regulations on how exactly the warning must be formatted, so a generic sticker doesn't really work. If you're just looking for scary looking stickers though, I think andy con was printing some and selling them on his website.
nice. the BIG SCARY LASER should help people realize its not just a normal laser pointer
and OP, you can save that pic and just erase the numbers and fill in your own using MS Paint or Photoshop or whatever you want to use. even use paint bucket and fill in the red with whatever color u are using.